For purposes of exercise and energy-saving and carbon reduction, cycling has become the fashion or trend worldwide. Whether as a vehicle or as a sports equipment, bicycles are indispensable.
Currently, mountain bikes (MTB) are the central type of bicycles. Some users of the MTBs like to additionally install an erect auxiliary handle (also “horn”) at an outer end of a handlebar grip. Such an auxiliary handle can provide an alternative holding gesture to bicycle riders. However, the auxiliary handles are always solely sold as an optional good in after market. Thus no cooperative design is made between the auxiliary handles and the grip. The installation of the auxiliary handle requires cutting an outer portion of the grip, whose width is the same as the auxiliary handle's, to expose the handlebar so that the auxiliary handle can then be fixed on the exposed portion. Such an installation requires using a knife to cut a tube-like object. For general users, there is some danger of injury in the operation. Furthermore, the cutting edge is difficult to be made neat. Irregular or notched cutting edges tend to be left. Exterior handsomeness must be adversely affected. On the other side, once the auxiliary handle is installed, the cut portion will be exposed again if the user removes the auxiliary handle. In other words, the original state of the grip can not be restored. The only solution is to replace the grip. Users can not make a reversible choice between installing and uninstalling the auxiliary handle. For users of bicycles, their choice for changing a handlebar grip is considerably restricted.